It is believed this artifact is a 37 kW (50 hp) Curtiss E-4, Serial Number 1, operated at a lower than normal rotational speed. It was the first of Curtiss water-cooled engines, and the second of two engines to power the U.S. Army Signal Corps Dirigible No. 1, the first U.S. military airship. The engine drove a tubular steel shaft about 6.7 m (22 ft) long on which was mounted a wooden propeller designed by Lt. Thomas E. Selfridge.

In 1908, the Signal Corps awarded Thomas Baldwin a contract for the construction of the airship not to exceed 36.6 m (120 ft), to be completely maneuverable, and to obtain a speed of 32 km/hr (20 mph). Baldwin piloted the airship, and Glenn Curtiss was the engineer. In the official speed run, the Baldwin airship reached 31.38 km/hr (19.61 mph).

 Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Date 1908 Country of Origin United States of America Type PROPULSION-Reciprocating & Rotary Manufacturer Curtiss Aeroplane and Motor Company
 Physical Description Type: Reciprocating, 4 cylinders, water cooled, in-line type Power rating: 14.9 kW (20 hp) at 450 rpm Displacement: 6.44 L (393 cu in) Bore and Stroke: 127 mm (5 in) x 127 mm (5 in) Weight: 114 kg (250 lb) Inventory Number A19280012000 Credit Line Gift of Mr. Gould Dietz Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
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